Square Force-Sensitive Resistor - Original
🧠 What Is It?
A Force-Sensitive Resistor (FSR) that detects pressure/force applied on its surface.
“Original” typically refers to high-quality, calibrated versions (e.g., Interlink-type FSRs).
The square sensing area allows uniform force detection over a flat surface.
🔍 Key Features
Analog Force Detection: Output varies with applied pressure
Thin & Flexible: Can be integrated into surfaces
Fast Response Time (<10 ms)
Lightweight & Durable
Wide Dynamic Range (light touch to heavy pressure)
Simple Interface (voltage divider circuit)
📊 Technical Specifications (Typical)
| Parameter | Value |
|---|---|
| Operating Voltage | 3.3 V – 5 V (via voltage divider) |
| Output Type | Analog (variable resistance) |
| Force Range | ~0.1 N to 100 N (approx.) |
| Response Time | <10 ms |
| Thickness | ~0.45 mm |
| Resistance (No Force) | >1 MΩ |
| Resistance (With Force) | ~1 kΩ – 10 kΩ |
| Repeatability | Good (better in original versions) |
⚙️ How It Works
The sensor has conductive layers separated by a pressure-sensitive material.
When force is applied, layers come closer → resistance decreases.
This resistance change is converted into voltage using a resistor divider.
Microcontroller reads voltage via ADC (analog input).
🔌 Basic Connection
One terminal → VCC (through fixed resistor)
Other terminal → Analog pin + GND
📌 Common setup:
Use a 10 kΩ resistor to form a voltage divider.
🧠 Working Behavior
No Force → Very High Resistance → Low Voltage Output
More Force → Lower Resistance → Higher Voltage Output
⚠ Output is non-linear → requires calibration for accurate force values.
📌 Applications
Pressure sensing pads
Touch-sensitive interfaces
Robotics (grip force sensing)
Wearable devices (foot pressure tracking)
Medical/rehabilitation devices
Interactive systems & gaming
⚠️ Important Notes
Not a Load Cell: Not suitable for precise weight measurement.
Non-linear Output: Requires calibration for better accuracy.
Force Distribution Matters: Works best with evenly applied force.
Wear Over Time: Repeated heavy pressure can degrade performance.
🛠 Summary
Type: Force-Sensitive Resistor (FSR)
Shape: Square sensing area
Output: Analog (resistance-based)
Best Use: Detecting presence and relative force
